Department of Orthopedics, The Affiliated Huai'an Hospital of Xuzhou Medical University, Huai'an, Jiangsu, China.
Department of Orthopedics, The Second People's Hospital of Huai'an, Huai'an, Jiangsu, China.
J Mol Histol. 2021 Apr;52(2):279-288. doi: 10.1007/s10735-020-09947-9. Epub 2021 Feb 2.
MicroRNA-27a (miR-27a) modulates osteogenic differentiation (OD); however, the mechanism by which it influences osteoclastic activity in the glucocorticoid (GC)-elicited osteoporotic bone is still unclear. Bone marrow was obtained from the proximal femur of patients (n = 3) with a femoral neck fracture and those (n = 3) with steroid-related osteonecrosis of the femoral head (ONFH). GC was applied to an established ONFH cell model from human bone marrow mesenchymal stem cells (hBMSCs). The miR-27a expression profiles were found to be downregulated in ONFH samples and GC-induced hBMSCs using microarray analysis and real-time quantitative polymerase chain reaction, whereas the OD capacity of hBMSCs was significantly reduced in the GC group compared with the control group. Subsequent transfection of an miR-27a mimic in hBMSCs revealed that the OD capacity of cells was remarkably strengthened in the GC group compared with the miR-control group. Bioinformatics software (TargetScan) predicted that phosphoinositide 3-kinase (PI3K) might be a potential miR-27a target, which was indicated by dual-luciferase reporter assay. Compared with the control group, the GC group exhibited a significantly downregulated protein expression level of PI3K and its downstream protein kinase B (Akt) and mammalian target of rapamycin (mTOR) expression. Furthermore, administration of 10 μM 740 Y-P, a cell-permeable phosphopeptide activator of PI3K, to hBMSCs increased the expression of Akt and mTOR. Treatment with 740 Y-P reversed the effect of miR-27a on OD in hBMSCs. In conclusion, miR-27a is thought to relieve ONFH and the OD repression in GC-induced hBMSCs by targeting the PI3K/Akt/mTOR pathway.
微小 RNA-27a (miR-27a) 调节成骨分化 (OD)；然而，其影响糖皮质激素 (GC) 诱发骨质疏松骨中破骨细胞活性的机制尚不清楚。从股骨颈骨折患者（n=3）和类固醇相关股骨头坏死（ONFH）患者（n=3）的近端股骨中获得骨髓。GC 应用于从人骨髓间充质干细胞（hBMSCs）建立的 ONFH 细胞模型。通过微阵列分析和实时定量聚合酶链反应发现，ONFH 样本和 GC 诱导的 hBMSCs 中 miR-27a 表达谱下调，而与对照组相比，GC 组 hBMSCs 的 OD 能力明显降低。随后在 hBMSCs 中转染 miR-27a 模拟物发现，与 miR-对照相比，GC 组细胞的 OD 能力显著增强。生物信息学软件（TargetScan）预测，磷酸肌醇 3-激酶（PI3K）可能是 miR-27a 的一个潜在靶点，双荧光素酶报告基因实验证实了这一点。与对照组相比，GC 组 PI3K 及其下游蛋白激酶 B（Akt）和哺乳动物雷帕霉素靶蛋白（mTOR）表达的蛋白表达水平显著下调。此外，向 hBMSCs 中添加 10 μM 740 Y-P，一种可渗透细胞的 PI3K 磷酸肽激活剂，可增加 Akt 和 mTOR 的表达。用 740 Y-P 处理可逆转 miR-27a 对 hBMSCs OD 的作用。总之，miR-27a 通过靶向 PI3K/Akt/mTOR 通路，缓解 GC 诱导的 hBMSCs 中的 ONFH 和 OD 抑制。
